1. Field of the Invention
The present invention relates to a video recording apparatus and method for recording a plurality of video images supplied and a centralized monitoring recording system capable of collecting video images to be monitored from a plurality of installed monitoring video cameras, recording them onto a recording medium such as a video tape, and monitoring them.
2. Description of the Related Art
In recent years, in the service trade such as a bank in which an automatic teller machine (ATM) is installed, a retail shop which is open until late at night, or a hotel, a monitoring video camera is widely installed for security. In each of the facilities, usually, a plurality of positions are to be monitored so that a plurality of monitoring video cameras have to be installed. Since it is not realistic that a person always monitors video images captured by the monitoring video cameras, usually, the captured video images are recorded by a video cassette recorder (VCR) or the like. When something happens, the recorded video images can be reproduced and watched.
The VCR is, however, usually expensive and the cost of installing VCR for the plurality of monitoring video cameras increases. Consequently, the video images from the plurality of monitoring video cameras are switched in a time division manner and captured in one system and the captured video images are recorded by one VCR. In this case, when the video images from the plurality of monitoring video cameras are recorded as they are sequentially on the same video tape, since the length of the video tape is limited, long-time continues recording cannot be performed.
For example, as disclosed in Japanese Unexamined Patent Application No. 10-108163, a method of reducing video images from a plurality of monitoring video cameras and compositing the reduced video images in combination to form one composite video image has been proposed. According to the method, the video images from the plurality of video cameras can be recorded at high density on a video tape having a limited length, so that recording of longer time can be realized.
One of the objects of the monitoring video system as described above is, when some problem occurs, to check monitoring video images recorded on the video tape later to analyze the status and cause of the problem. Consequently, additional information such as recording date and time is recorded in association with recorded data of each frame or field. For example, in a conventional analog recording system, recording is performed so that additional data is inserted in a vertical blanking period for an image of each field. Since only one video image is included in one field, the correspondence between the video image and the additional data is clear.
In a system of reducing a plurality of video images and combining them to thereby form one composite video image as described above, however, when the composite image in a frame or field and the additional data are associated with each other in a manner similar to the conventional one, from the additional data, the corresponding reduced video image in the composite video image cannot be specified. There is consequently a problem such that, when some trouble occurs and data on the video tape is analyzed later, the additional data cannot be effectively used.